It is well known in the electronic arts to position and interconnect electronic components on printed wiring boards or printed wiring assemblies (PWA's). In large electronic systems, comprising several PWA's, it is also well known to electrically interconnect the PWA's through a back-plane or "motherboard".
A common technique for coupling multiple PWA's to a back-plane is to provide one or more connectors along one edge of each PWA, with appropriate pins of each connector being electrically connected to appropriate wiring runs on the PWA, and to provide an appropriate mating connector on the back-plane. Each PWA is thus physically secured and electrically coupled to the back-plane by pressing the PWA connector into the back-plane connector.
In complex systems, such as digital computers, it is common for each PWA to have multiple back-plane connectors. Each such connector may comprise many pins. The physical force required to insert and extract a PWA from the back-panel connectors becomes quite significant, due to the frictional forces between the pins of one connector and the sockets of the other connector. For example, for a PWA having three 96-pin connectors, a force of approximately 40-60 pounds is required to insert the PWA into the back-plane and only slightly less force is required to extract the PWA from the back-plane.
Due to the large forces required to extract PWA's from their associated back-planes, it is quite difficult for an assembly person or repair person to grasp the PWA with sufficient force to extract it. Often there may be no convenient means on the PWA to grasp. Indeed, various U.S. and foreign electrical underwriting associations are at the present time requiring that, due to the potential danger of electrical shock to a user, there be no convenient knobs, pulls, etc. situated on the exterior surface of the PWA to facilitate extraction by hand, and such associations require that PWA's be designed so that some form of tool must be used to extract them from the unit.
Also in the typical office environment there is often rather limited access to the data processing equipment, so it is quite advantageous to be able to extract the PWA from the back-plane with one hand.
There is therefore an urgent need in the electronic arts for a convenient tool to insert and extract large PWA's from their associated back-planes.